The invention relates generally to the field of antennas.
Most antennas for satellite communications or GPS are omni-directional and do not have a null at the horizon. Other directional antennas must be pointed directly at the satellite. These antennas have better gain, but require a movable mount and a mechanical or electrical tracking system if the satellites are not geo-stationary. During operation directional antennas require extra time for aiming at the satellite, making them more difficult to use on the battlefield. One particular type of antenna, controlled radiation pattern antennas (CRPA's), have generally been effective against jammers. Although CRPA's can null jamming or interference source at any elevation angle, they can null only a small number of interference sources. Because the CRPA antenna array is large and the adaptive beamformer requires a sizable power source, CRPA's are not readily transportable by a user.
Therefore, there is a need for a small, lightweight, easily concealed, wideband, wide beam pattern, readily human transportable and deployable antenna that is able to transmit and receive signals to and from satellites at any position relative to the antenna, and that can also null jamming or interference sources near the horizon.